This invention relates generally to turbomachinery, and specifically to rotor blade and stator vane airfoils for the compressor and turbine sections of a gas turbine engine, or the fan section of a turbofan engines. In particular, the invention concerns airfoil tip fabrication and restoration, and manufacturing, maintenance and repair methods for new and engine-run rotor blade and stator vane airfoils.
Gas turbine engines provide reliable, efficient power for a wide range of applications, including aviation and industrial power generation. In typical designs, the power core is formed of a compressor, combustor and a turbine, arranged in flow series with an upstream inlet and downstream exhaust.
The compressor section compresses air from the inlet, which is mixed with fuel in the combustor and ignited to generate hot combustion gas. The turbine section extracts energy from the expanding combustion gas, and drives the compressor via a common shaft. Energy is delivered in the form of rotational energy in the shaft, reactive thrust from the exhaust, or both.
Small-scale gas turbines generally utilize a one-spool design, with co-rotating compressor and turbine sections. Larger-scale combustion turbines including aircraft engines and industrial gas turbines (IGTs) are typically arranged into a number of coaxially nested spools, which operate at different pressures and temperatures, and rotate at different speeds.
The individual compressor and turbine sections in each spool are subdivided into a number of stages, which are formed of alternating rows of rotor blade and stator vane airfoils. The airfoils are shaped to turn, accelerate and compress the working fluid flow, and to generate lift for conversion to rotational energy in the turbine.
Aviation applications include turbojet, turbofan, turboprop and turboshaft engine configurations. Turbojets are an older design, in which thrust is generated primarily from the exhaust. Modern fixed-wing aircraft typically utilize turbofan and turboprop engines, in which the low pressure spool is coupled to a propulsion fan or propeller. Turboshaft engines are used on rotary-wing aircraft, including helicopters.
Across these applications, gas turbine engine components are subject to substantial operational wear and tear from working fluid, and exposed to high levels of rotational stress and strain. As a result, regular inspections and maintenance are required, particularly for the tip sections of blade and vane airfoils in the compressor, turbine and fan.